VEKTEBEATA. 265 



Cope, Prof. E. D. On some extinct types of horned Perissodactyles. 

 Proc. Amer. Assoc, vol. xxii. B. pp". 108, 109. 



The Miocene formation in W, America " embraced several genera 

 and species of horned giants not very unlike the Eohasilius and Uinta- 

 therium in their armature." . G. A. L. 



■ . Eeport on the Stratigrapliy and Pliocene Vertebrate Palae- 

 ontology of Northern Colorado. Bull. Gcol. Surv. Territories, 

 no. 1, pp. 1-28. 



The age of the deposits has been determined by palaeontological evi- 

 dence solely. They lie between the South Platte river and the Lodge- 

 Pole Creek. The Pliocene sandstone is believed to represent a swamp- 

 formation. Beneath it is a bed of white friable argillaceous Miocene 

 rock, probably of the White River epoch, several hundred feet thick ; 

 lower still a dark-coloured argillaceous rock apparently of freshwater 

 origin, believed to be Cretaceous. " In the Pliocene strata above 

 described, mammalian remains are exceedingly abundant over limited 

 areas, those of horses in an especial manner The most impor- 

 tant palaeontological results are: — 1, the discovery that the camels of 

 this period possessed a full series of upper incisor teeth ; 2, that the 

 horses of the genus Protohippus are, like those of Ilippotherium, three- 

 toed ; 3, that a Mastodon of the M. ohioticus type existed during the 

 same period." 



The following new species are described : — Hippotherium paniense, 

 Frotohippus Idbrosus, P. sejunctus, Procamelus heterodontus, Merycodus 

 gemmifer, Menotherium lemuriminif Hypertragulus tricostatuSy ElotTie- 

 rium ramosum, L. C. M. 



. Eeview of the Yertebrata of the Cretaceous Period found 



west of the Mississippi Eiver. Bull. U.S. Geol. Surv. Territories, 

 no. 2, pp. 1-77. 



Messrs. Meek and Hayden had subdivided the Cretaceous beds of 

 the West into: — 1. The Dakota Group (Missouri River, Rio Graude, 

 New Mexico). 2. The Benton Group (Missouri River, Smoky-Hill 

 River, Kansas, Texas). 3. The Niobrara Group (Missouri River, 

 Kansas, Texas). 4. The Pierre Group (Nebraska, Dakota, Middle 

 Colorado), corresponding to the lower bed of Grecnsand of New Jersey. 

 5. The Pox-Hills Group (Dakota, Colorado), corresponding to the 

 second bed of Grecnsand of New Jersey. The beds are enumerated 

 in ascending order, and all are marine. Above them are found rocks 

 of brackish or freshwater origin, comprising sandstones, shales, and 

 lignites. 6. The Fort-Union or Lignite Group (from the Missouri 

 valley to Colorado, passing under Tertiary beds by the way). 7. The 

 Bitter-Creek Group (Wyoming). 8. The Bear-River Group (Wyoming 

 River) ; perhaps contemporaneous with No. 7. 



Very conflicting opinions arc cited as to the ago of the last three 

 groups. They have usually been considered Tertiary. Professor Cope 

 draws the lino between Cretaceous and Tertiary at the top of No. 7. 



